1. Field of the Invention
The present invention relates to an optical waveguide device which is disposed on an edge of a detection region defined by a rectangular panel, such as an optical touch panel and an optical shape sensor, and which forms a lattice of light beams in the detection region.
2. Description of the Related Art
In the past, an optical detection means for optically detecting the location of a finger and the like using an optical waveguide has been used as one of the means for detecting the location of a touch on a touch panel, as disclosed in Japanese Unexamined Patent Application Publication Nos. 2010-20103 and 2010-32378.
This optical detection means is configured such that a light-emitting section of a light-emitting optical waveguide device provided on left-hand and right-hand side portions on opposite side of a corner of a rectangular panel (or a screen or the like) emits a large number of substantially parallel light beams toward other side portions opposed to the above-mentioned left-hand and right-hand side portions, with the detection region of the panel therebetween, to form a lattice of light beams within the detection region, and such that a light-receiving element or the like detects light beams incident on a light-receiving section of a light-receiving optical waveguide provided on the other sides of the panel. In this state, when an object such as a finger blocks some of the light beams within the detection region, the light-receiving element or the like connected to the light-receiving optical waveguide senses where some light beams are blocked, so that the location (i.e., X and Y coordinates) of the finger touch or the like is specified.
FIG. 3 is a schematic view showing a core pattern of a conventional light-emitting optical waveguide device used for the above-mentioned touch panel and the like. The reference character P designates a rectangular panel having a pair of long sides X (extending in the x-direction), and a pair of short sides Y (extending in they-direction). The reference character D1 designates the light-emitting optical waveguide device including an optical waveguide having cores indicated by dotted lines, and D2 designates a light-receiving optical waveguide device including an optical waveguide having cores indicated by dash-double-dot lines.
As shown in FIG. 3, the cores of the conventional light-emitting optical waveguide device D1 diverge just ahead of their proximal ends 20a which receive light beams from a light source 10 into a plurality of light-emitting cores 20b extending along a long side X of the panel P, and a plurality of light-emitting cores 20c extending along a short side Y thereof. The light beams coming from the light source 10 into the cores are distributed to the large number of light-emitting cores 20b and 20c, and are emitted outwardly from distal ends of the respective light-emitting cores 20b and 20c, as disclosed in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2001-514779.